A Comparison of the Performance of Environmentally Friendly Anhydrous Fire Resistant Hydraulic Fluids

Abstract

Abstract Many industries benefit from using fire resistant hydraulic fluids including aviation, steel processing, aluminum die-casting, marine, mining, and many more. In recent years, environmental performance has become an increasingly important feature of hydraulic fluids notably in Europe with the introduction of the European Eco-Label and in the United States with the recommendations provided by the 2002 U.S. Farm Bill for procurement of bio-based materials by Federal agencies. Environmental performance favors esters and vegetable oils as the preferred technologies today but polyalkylene glycols (PAGs) offer an alternative option although they are not derived from renewable sources. The performance of several environmentally friendly fire resistant anhydrous hydraulic fluids based on these technologies has been evaluated in laboratory bench tests. All fluids exhibit excellent hydraulic vane pump wear performance. In high temperature oxidation studies, synthetic products based on esters and PAGs, out-perform vegetable oils. Hydrolytic stability results show hydrolysis of synthetic esters and vegetable oils occurs to form acids in contrast to a PAG formulation, which is more stable. Furthermore the unique water solubility and non-sheening aspects of the PAG product indicate it may be a more favorable choice for use in applications where fluid leakage into water-ways is a concern. By understanding the performance of each product technology, direction can be provided in the type of equipment and industries where these fluids can be used and a discussion pertaining to this is presented herein.